1. experimental method: this is the most direct research method, and the change of results is observed by controlling variables. This method can provide the most direct evidence, but it needs a lot of time and resources.
2. Observation method: This method includes direct observation and recording of phenomena. This method is simple, but it may be influenced by the bias of observers.
3. Survey method: This method usually involves a questionnaire survey or interview with a group of people or things. This method can collect a lot of data, but there may be subjectivity and error of the interviewee.
4. Case study method: This method involves in-depth study of specific individuals or events. This method can provide in-depth understanding and detailed description, but it may not be extended to a larger group.
5. Comparison method: This method includes comparing two or more objects. This method can help researchers find similarities and differences, but it needs to ensure that the objects of comparison are similar.
6. Statistical analysis method: This method involves statistical processing and analysis of data. This method can help researchers find patterns and trends in data, but it requires certain statistical knowledge and skills.
7. Simulation method: This method includes using computer models to simulate real-world situations. This method can save time and resources, but it may not completely replicate the complexity of the real world.
When choosing research and experimental design methods, researchers need to consider research objectives, available resources, reliability and validity of data and other factors.